+ The source distribution of <code>gedcom-parse</code> contains an example implementation (<code>utf8-locale.c</code> and <code>utf8-locale.h</code>
+ in the top directory). Feel free to use it in
+your source code (it is not part of the library, and it isn't installed anywhere,
+so you need to take over the source and header file in your application).
+ <br>
+ <br>
+
+Its interface is:<br>
+ <blockquote><pre><code>char *<b>convert_utf8_to_locale</b> (char *input, int *conv_failures);<br>char *<b>convert_locale_to_utf8</b> (char *input);<br></code></pre></blockquote>
+
+Both functions return a pointer to a static buffer that is overwritten on
+each call. To function properly, the application must first set the
+locale using the <code>setlocale</code> function (the second step detailed below).
+ All other steps given below, including setting up and closing down the conversion
+handles, are transparantly handled by the two functions. <br>
+ <br>
+If you pass a pointer to an integer to the first function, it will be set
+to the number of conversion failures, i.e. characters that couldn't be converted;
+you can also just pass <code>NULL</code> if you are not interested (note that usually, the interesting information is just whether there <i>were</i>
+ conversion failures or not, which is then given by the integer being bigger
+than zero or not). The second function doesn't need this, because any
+locale can be converted to UTF-8.<br>
+ <br>
+
+You can change the "?" that is output for characters that can't be converted
+to any string you want, using the following function before the conversion
+calls:<br>
+ <blockquote><pre><code>void <b>convert_set_unknown</b> (const char *unknown);</code></pre></blockquote>
+ <br>
+If you want to have your own functions for it instead of this example implementation, the following steps need to
+be taken by the application (more detailed info can be found in the info
+file of the GNU libc library in the "Generic Charset Conversion" section
+under "Character Set Handling" or online <a href="http://www.gnu.org/manual/glibc-2.2.3/html_chapter/libc_6.html#SEC99">here</a>):<br>
+ <ul>
+ <li>inclusion of some headers:</li>
+ </ul>
+ <blockquote>
+ <blockquote>
+ <pre><code>#include <locale.h> /* for setlocale */<br>#include <langinfo.h> /* for nl_langinfo */<br>#include <iconv.h> /* for iconv_* functions */<br></code></pre>
+ </blockquote>
+ </blockquote>
+ <ul>
+ <li>set the program's current locale to what the user configured in the environment:</li>
+ </ul>
+ <blockquote>
+ <blockquote>
+ <pre><code>setlocale(LC_ALL, "");</code><br></pre>
+ </blockquote>
+ </blockquote>
+ <ul>
+ <li>open a conversion handle for conversion from UTF-8 to the character set of the current locale (once for the entire program):</li>
+ </ul>
+ <blockquote>
+ <blockquote>
+ <pre><code>iconv_t iconv_handle;<br>...<br>iconv_handle = iconv_open(nl_langinfo(CODESET), "UTF-8");</code><br>if (iconv_handle == (iconv_t) -1)<br> /* signal an error */<br></pre>
+ </blockquote>
+ </blockquote>
+ <ul>
+ <li>then, every string can be converted using the following:</li>
+ </ul>
+ <blockquote>
+ <blockquote>
+ <pre><code>/* char* in_buf is the input buffer, size_t in_len is its length */<br>/* char* out_buf is the output buffer, size_t out_len is its length */<br><br>size_t nconv;<br>char *in_ptr = in_buf;<br>char *out_ptr = out_buf;<br>nconv = iconv(iconv_handle, &in_ptr, &in_len, &out_ptr, &out_len);</code></pre>
+ </blockquote>
+ </blockquote>
+ <blockquote>If the output buffer is not big enough, <code>iconv</code> will return -1 and set <code>errno</code> to <code>E2BIG</code>. Also, the <code>in_ptr</code> and <code>out_ptr</code> will point just after the last successfully converted character in the respective buffers, and the <code>in_len</code> and <code>out_len</code> will be updated to show the remaining lengths. There can be two strategies here:<br>
+ <ul>
+ <li>Make sure from the beginning
+that the output buffer is big enough. However, it's difficult to find
+an absolute maximum length in advance, even given the length of the input
+string.<br>
+ <br>
+ </li>
+ <li>Do the conversion in several steps, growing the output buffer each time to make more space, and calling <code>iconv</code>
+ consecutively until the conversion is complete. This is the preferred
+way (a function could be written to encapsulate all this).</li>
+ </ul>
+Another error case is when the conversion was unsuccessful (if one of the
+characters can't be represented in the target character set). The <code>iconv</code> function will then also return -1 and set <code>errno</code> to <code>EILSEQ</code>; the <code>in_ptr</code> will point to the character that couldn't be converted. In that case, again two strategies are possible:<br>
+ <ul>
+ <li>Just fail the conversion, and show an error. This is not very user friendly, of course.<br>
+ <br>
+ </li>
+ <li>Skip over the character that can't be converted and append a "?" to the output buffer, then call <code>iconv</code> again. Skipping over a UTF-8 character is fairly simple, as follows from the <a href="http://www.cl.cam.ac.uk/%7Emgk25/unicode.html#utf-8">encoding rules</a>:</li>
+ </ul>
+ <ol>
+ <ol>
+ <li>if the first byte is in binary 0xxxxxxx, then the character is only one byte long, just skip over that byte<br>
+ <br>
+ </li>
+ <li>if the first byte is in binary 11xxxxxx, then skip over that byte and all bytes 10xxxxxx that follow.<br>
+ </li>
+ </ol>
+ </ol>
+ </blockquote>
+ <ul>
+ <li>eventually, the conversion handle needs to be closed (when the program exits):<br>
+ </li>
+ </ul>
+ <blockquote>
+ <blockquote>
+ <pre><code>iconv_close(iconv_handle);<br></code></pre>
+ </blockquote>
+ </blockquote>
+ The example implementation
+mentioned above grows the output buffer dynamically and outputs "?" for characters
+that can't be converted.<br>
+
+ <hr width="100%" size="2">
+ <h2><a name="Support_for_configure.in"></a>Support for configure.in</h2>
+Programs using the GEDCOM parser library and using autoconf to configure
+their sources can use the following statements in configure.in (the example
+is checking for gedcom-parse, version 1.34):<br>
+ <blockquote><code>AC_CHECK_LIB(gedcom, gedcom_parse_file,,<br>
+ AC_MSG_ERROR(Cannot find libgedcom: Please install gedcom-parse))<br>
+AC_MSG_CHECKING(for libgedcom version)<br>
+AC_TRY_RUN([<br>
+#include <stdio.h><br>
+#include <stdlib.h><br>
+#include <gedcom.h><br>
+int<br>
+main()<br>
+{<br>
+if (GEDCOM_PARSE_VERSION >= 1034) exit(0);<br>
+exit(1);<br>
+}],<br>
+ac_gedcom_version_ok='yes',<br>
+ac_gedcom_version_ok='no',<br>
+ac_gedcom_version_ok='no')<br>
+if test "$ac_gedcom_version_ok" = 'yes' ; then<br>
+ AC_MSG_RESULT(ok)<br>
+else<br>
+ AC_MSG_RESULT(not ok)<br>
+ AC_MSG_ERROR(You need at least version 1.34 of gedcom-parse)<br>
+fi</code><br>
+ </blockquote>
+
+There are three preprocessor symbols defined for version checks in the header:<br>
+ <ul>
+ <li><code>GEDCOM_PARSE_VERSION_MAJOR</code></li>
+ <li><code>GEDCOM_PARSE_VERSION_MINOR</code></li>
+ <li><code>GEDCOM_PARSE_VERSION</code><br>
+ </li>
+ </ul>
+The last one is equal to <code>(GEDCOM_PARSE_VERSION_MAJOR * 1000) + GEDCOM_PARSE_VERSION_MINOR.</code><br>
+<hr width="100%" size="2">